1. Field of the Invention
The present invention relates to a network system, and more particularly, to a mobile Internet Protocol (IP) system and a data routing method of the mobile IP system.
2. Discussion of the Related Art
As demands for the multimedia services of personal computers are increasing at a very drastic rate, the high-speed network systems based on the Asynchronous Transfer Mode (ATM) technology are being widely used for both of the Wide Area Networks (WAN) and Local Area Networks (LAN). In spite of such steep growth in the network technology, many people still use the Internet service. Therefore, various schemes of accommodating Internet Protocols (IP) to such high-speed networks are being suggested from many Internet Engineering Task Force (IETF) and ATM forums, and their international standards are being formed.
Additionally, in accordance with the fact that the mobile communication technology is becoming more sophisticated and advanced, the wire and wireless network systems should be able to be linked to each other or combined together for future network systems. Some of the examples of researches providing the mobility of Internet networks or ATM networks are the mobile IP of the IETF and the wireless ATM of the ATM forum and ETSI Broadband Radio Access Network (BRAN).
The Wireless ATM Working Group (WATM WG) is trying to apply the ATM technology, which was used primarily in the wire networks only, to the wireless networks, and the IETF is focusing on providing mobility of a mobile node in the wireless networks by integrating the routing protocols of the mobile node.
The IP version 4, which is used in most Internet environments, presumes that it can identify a node (host or router) by using its IP address. Therefore, in order for a node to receive data, the node must be located in the network that includes its IP address. If the location of the node changes, the data may not be able to be transmitted properly.
If a node needs to change its connecting point, the node must change its IP address. In addition, the address of the changed host must be known throughout the Internet network. However, when the location of the node is changed, it is very difficult to maintain the connectivity between its transport layer and upper layer. In addition, as the number of the mobile nodes increases, it may not be able to accommodate all the mobile nodes.
A standard scheme for providing mobility of the node in an Internet network is currently being developed by the IETF, and this is called as a mobile IP system. The mobile IP system eliminates most of the problems described above. However, when the location of the mobile node in the network is changed while the node receives the data packets, the data packets being transmitted after such change will be lost.